Shown above is a sample of the type of color images that you will be asked to identify by your medial examiner.  In each of the above circles is a number. If you can identify the numbers of each of the circles, then chances are you have no color vision deficiencies.

Federal Aviation Regulations, according to the third-class qualifications, sec. 67.303 says: Eye standards for a third-class airman medical certificate are: (a) Distant visual acuity of 20/40 or better in each eye separately, with or without corrective lenses. (b) Near vision of 20/40 or better in each eye separately, with or without corrective lenses. ** Note: if corrective lenses are required to obtain the minimal 20/40 vision, then the person is eligible only on the condition that the corrective lenses MUST be worn while exercising the privileges of an airman certificate.

An eye examination is a battery of tests performed by an ophthalmologist, optometrist, or orthoptist assessing vision and ability to focus on and discern objects, as well as other tests and examinations pertaining to the eyes. Health care professionals often recommend that all people should have periodic and thorough eye examinations as part of routine primary care, especially since many eye diseases are asymptomatic. Eye examinations may detect potentially treatable blinding eye diseases, ocular manifestations of systemic disease, or signs of tumours or other anomalies of the brain.

Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths (or frequencies) of the light they reflect, emit, or transmit. The nervous system derives color by comparing the responses to light from the several types of cone photoreceptors in the eye.

These cone photoreceptors are sensitive to different portions of the visible spectrum. For humans, the visible spectrum ranges approximately from 380 to 740 nm, and there are normally three types of cones. The visible range and number of cone types differ between species.

Color processing begins at a very early level in the visual system (even within the retina) through initial color opponent mechanisms. Opponent mechanisms refer to the opposing color effect of red-green, blue-yellow, and light-dark. Visual information is then sent back via the optic nerve to the optic chiasma: a point where the two optic nerves meet and information from the temporal (contralateral) visual field crosses to the other side of the brain. After the optic chiasma the visual fiber tracts are referred to as the optic tracts, which enter the thalamus to synapse at the lateral geniculate nucleus (LGN).

The LGN is divided into two zones: the M-zone, consisting primarily of M-cells, and the P-zone, consisting primarily of P-cells. The M- and P-cells make up the principal sublayers, while each layer has a koniocellular sublayer. M- and P-cells received relatively balanced input from both L- and M-cones throughout most of the retina, although this seems to not be the case at the fovea. The koniocellular sublayer receives axons from the small bistratified ganglion cells, which directly compare the output of S-cones and L/M-cones, giving rise to the blue-yellow opponent mechanisms.